Can't Get Ammonia Back Down In 10 Month Old Tank Please Help!

[JALouis]

HI,

My 55 gallon tank has been fishless cycled (thanks to the help of people here) and has had fish in the tank for at least 4 months (after the fishless cycle was complete). All of a sudden I started getting an ammonia reading of .25. This time I'm struggling with getting the level down. I've been doing frequently water changes (all along weekly about 25% and just recently every 3 days about 25% to get try to get the ammonia levels down). The nitrite are 0 and have not moved. The Nitrate level hasn't gone above 20ppm since the tank cycled. The water is pretty clean and there is not much coming up when I siphon (vacuum) the gravel. I do use a tap water conditioner before adding new water into the tank. The temperature stays stable at around 75 degrees.

I noticed last month a similar thing happened that the ammonia rose but then went back down to 0 after a filter media change (it was time anyway). Last weekend since it was time I changed the charcoal and and floss in the filter but the ammonia still hasn't dropped to 0. It's still around .25. Could the carbon (there are 2 bags in the canister filter) be pushing the ammonia back out? Could my ammonia test liquid be bad? I didn't see an expiration date on the bottle. Should I try a new set of bottles?

I have to admit the tank is slightly overstocked (based on the full size of the fish though they aren't there full size). In the tank are 5 bosemani rainbow fish (who surprisingly seem perfectly fine and happy), 6 tiger barbs (one seems to be affected by the ammonia level and is struggling), 2 fan shrimp (who even with the ammonia level have been molting. One has even molted twice now in less than 4 weeks) and a black ghost (who seems perfectly happy as well. No slits in the fins).

Does anyone have any ideas as to why the ammonia increased and why I can't get it back down to 0? What should I do? I want to avoid using Ammo Lock or anything else if possible.

Any suggestions would be helpful.

Thank you!

 

[waterdrop]

Well this sounds like an interesting, potentially difficult one to figure out. It will be interesting to see what ideas come from the members.

I suppose if you are already slightly overstocked by your own estimate, the gradual growth of the fish may be the culprit. The capacity of the biofilter may have been just serving them the as they've grown a bit larger they've finally exceeded it.

Another factor might be the ratio of biomedia to chemical media. You've stated that you have "2 bags" of carbon in the filter and, without seeing it, that could be a lot, considering it will be very poor at any biological contribution -- maybe is taking too much space away from having more biomedia, like ceramics or sponges, which would hold a lot more bacteria.

Perhaps a discussion the the filter type and descriptions of the amounts of media might help the commentators who come along behind me...

~~waterdrop~~

 

[Piltdownpaul]

Could be a long shot but ages ago i had a problem with ammonia not going down for days and the culprit was a dead fish trapped in some plants which was hidden until i had a root around!

 

[JALouis]

Thanks Waterdrop. It is an interesting problem. The fish are not full size yet, but that could very well be the issue, if they have grown bigger than the bacteria can handle. Would it make sense if that's the case that more bacteria should grow and eventually catch up? Is there anything I can do to lower the ammonia or speed up the bacteria growth. The fish still all seem ok. The tiger barbs that I was sure would be a goner by now is still hanging in there as well. However, I do not want the ammonia to increase anymore.

The filter actually calls for 3 bags of carbon but I only leave 2 in.

Thanks again for your help.
Jennifer

Could be a long shot but ages ago i had a problem with ammonia not going down for days and the culprit was a dead fish trapped in some plants which was hidden until i had a root around!

I thought about that but all the fish I had are all still accounted for.

 

[lizandel]

OK, so I am very new to this so I may be way off track...

I wondered if its something to do with the media you are using in your filter and if it contains enough surface area for a bacteria colony that is big enough to deal with the ammonia in your tank.

 

[waterdrop]

Yes, lizanddel is on track. Yes, the bacteria in a normal tank and filter will keep growing along with the fish. As the fish get bigger and eat more and give off more NH3 and produce more waste that turns in to NH3, the larger food source will allow the Nitrosomonas colonies to expand and thus the biofilter will enlarge to handle the greater bioload. But what I was worried about was that if the total surface area of the biomedia is too small, the filter may run out of the capacity to handle enough ammonia oxidizing colonies to handle the bioload. (this of course is what the rough one inch stocking guideline is all about.. its trying to lower your risk of this situation) And of course this is why overstocking is always accompanied by discussions of having oversized filters or extra filters.

~~waterdrop~~

 

[MrPurplePickle]

Whats your Ph JA?

 

[drobbyb]

OK, so I am very new to this so I may be way off track...

I wondered if its something to do with the media you are using in your filter and if it contains enough surface area for a bacteria colony that is big enough to deal with the ammonia in your tank.

This was my initial thought too. Sounds like insufficient media. Try taking the carbon out altogether and replace it with some ceramic noodles or an open celled sponge. Until the new media gets colonized you will need to treat it like a fish in cycle. Make sure you keep the ammonia level below .25.

To help explain why this may have happened, I agree with waterdrop, your fish have probably grown over the time they have been in the tank leading to a higher bio load. Your filter may not be enough to handle the higher load.

 

[arobinson1984]

Personally, I just think you are probably experiencing a slight ammonia spike.

You mentioned that you changed the filter media a month ago and had a small spike then, and you also mention that you changed the carbon pads and filter floss last weekend. If the carbon pads have been in a while they will have lost their effectiveness and will basically be operating as an additional biological media so if you have changed these and the filter floss in one go then you have probably removed a fair amount of good bacteria hence the slight ammonia spike.

Only replace the main filter media when its literally falling apart, dont replace it every 'x' amount of months as stated in the instructions, these are just aimed at trying to get you to purchase more sponges on a regular basis. With a good siwsh in old tank water on a regular basis, the main media sponges should last years.

Carbon is not needed in a filter 24/7, carbon is chemical filtration and is used to remove toxins from the water such as medications, after about 3-4 days the carbon loses its effectiveness so you would probably be better using another form of biological media for more benefit.

Andy

 

[JALouis]

Thanks for everyone's help. I'm going to try to answer everyone's questions.

My Ph is always between 6.2 and 7. It usually stays around 6.8. It was between 6.8 and 7 when I tested it a couple of days ago.

The ammonia spike last time occured before I changed the media in the filter and then dropped back to 0 after the media change.

I would tend to agree with Waterdrop and Lizandel and Drobbyb that there isn't any more room for the bacteria to grow but the canister filter I have is for a 100 gallon tank and the tank is only 55 gallon. I definitely do not have a 100 gallons of fish in there. When I figure out the stocking formula (1 inch of fish full grown = 1 gallon), it comes out to 66 gallons. This is mostly due to the full size of the black ghost at 18 inches.

I accidentally moved a plant (artificial) one when removing the molt shell (they are fan shrimp so they won't eat the shell) and noticed a lot of matter coming up. I'm going to do a water change today and will concentrate on the areas under the plant and see if that is the cause.

Any other ideas would be appreciated.

Thanks!